Questions regarding points of extremely high mass density, which creates an extremely strong gravitational field from which light cannot escape.

learn more… | top users | synonyms

5
votes
3answers
160 views

Are black holes expanding?

We know that it is a commonly heard claim that in every black hole there is a universe. It is also believed that the universe is expanding. If we use both of these, can we conclude that every black ...
4
votes
2answers
146 views

How could we detect planets orbiting black holes?

Detecting planets orbiting around stars can be made with several methods, transit photometry seems to be by far the most popular method nowadays. I wonder how we could detect planets orbiting black ...
2
votes
1answer
73 views

Is the sphere of influence of our milky way's center super massive black hole same as the Milky way's radius?

The sphere of influence is a region around a supermassive black hole in which the gravitational potential of the black hole dominates the gravitational potential of the host galaxy(found it in wiki). ...
6
votes
2answers
165 views

Why do black holes choke?

I read that a black hole can sometime "choke" on a star: "...the disrupted stellar matter was generating so much radiation that it pushed back on the infall. The black hole was choking on the ...
2
votes
2answers
97 views

Would all neutron stars inevitably collapse into black holes due to quantum tunneling?

The materials inside a neutron star are densely packed (extremely close to each other) and as time goes by say about an eon later, most of the neutrons would eventually tunnel into each other and ...
1
vote
2answers
98 views

Can any stars ever form supermassive black holes?

I heard that most supermassive blackholes are not formed by stars – in fact, we aren't even sure how they're formed. But could a star, with enough mass and low enough metallicity, form a supermassive ...
1
vote
2answers
117 views

Can earth escape sun's gravity with the help of a black hole heading towards our solar system?

To escape the Sun's gravity, the Earth would need sufficient amount of energy. Let's say a stellar black hole has entered our solar system and at a certain distance from earth, the black hole exerts ...
2
votes
1answer
87 views

Does gravity bend light, and how much time does it take for light to cross gravity of a Black Hole?

This is very confusing to me, so the question might be same. Please go through it, if required i will add more text. According to Einstein's theory of general relativity, photons are not technically ...
4
votes
1answer
155 views

Two black holes photo interpretation

Please see this image: I wonder two things about these black holes. The first is, what are the oblong, smaller black hole-looking voids outside the perimeter of the major black holes? Also, why are ...
3
votes
1answer
331 views

Why do certain massive stars leave no remnants?

Mass and metallicity are the two main determinants for a star's fate. This is simple enough. What's more complicated is how exactly these determine the star's fate. For example, you can see in this ...
1
vote
1answer
53 views

A black hole that doesn't take in matter?

According to List of Common Misconceptions by Wikipedia, under the heading of astronomy, this line can be found: A black hole can act like a "cosmic vacuum cleaner" and pull a substantial ...
2
votes
2answers
99 views

A star a black hole and planets around them

Imagine we have a black hole and a star. There are very close to each other so black hole slowly consumes the star. It is possible to have planets in this system, and for them not to be consumed by ...
2
votes
1answer
74 views

If any object could become a black hole, could any object become a neutron star?

A black hole doesn't necessarily need to form from a star; theoretically, it could form from any extremely dense object. In fact, many astronomers differentiate certain black holes, like supermassive ...
1
vote
1answer
359 views

Does this black hole magnetohydrodynamics equation even superficially make sense?

My question is about the journal paper mentioned in an Academia Stack Exchange post. Please understand that this paper has never been posted on arXiv, and I can provide only a link whose content is ...
1
vote
1answer
89 views

What's the difference between the apparent horizon and event horizon of a black hole?

The Wikipedia page for apparent horizon is pretty sketchy and requires some GR knowledge. Is there any simple definition?
3
votes
2answers
55 views

Luminosity of black hole accretion disc

The luminosity of a black hole accretion disc gaining mass at a rate $dM\over dt$ can be estimated as ${1\over 12}{dM\over dt}c^2$ That is a substantial proportion of the rest mass of the in-falling ...
3
votes
1answer
166 views

Is a black hole heavier than the star from which it was created?

I did some googling around and couldn't get answer to a simple question of black hole mass compared to the star from which it was created. It is well known that giant stars burn very bright and ...
4
votes
2answers
241 views

Can we compress any object to create black Holes?

In general, when a star runs out of nuclear fuel, gravity gets the upper hand and the material in the core is compressed even further and creates black holes. I am clear till here. Now the question ...
4
votes
3answers
318 views

Is a black hole a perfect sphere?

I know all about how black holes form and why their gravity is so strong. However, is the gravity equally powerful in all directions? Will the event horizon appear as a perfect sphere?
2
votes
2answers
62 views

Linear extent of an accretion disk

I have a homework assignment question on accretions discs (essentially an estimation of the number of electron scatterings, but this is just for background). There are a few parameters, one of them ...
1
vote
1answer
114 views

How gravity works in a black hole? [closed]

In astronomy class, we have to state how gravity work in the black hole? I know for one fact is that black hole is strong enough to stretch you thin enough like a noodle. Any ideas?
0
votes
3answers
273 views

What will happen if a black hole appears near our solar system?

We know that black hole possesses immense power and can destroy anything coming in front of it's path. If such a black hole appears near our solar system, are we going to survive? Is there any way not ...
4
votes
2answers
114 views

Is antimatter also attracted by gravitational field?

As we all know matter is attracted by the gravitational field of black hole. So, my question is: Is there any possibility of a black-hole attracting antimatter? Can you explain how/why please?
4
votes
2answers
80 views

Conversion of matter into antimatter

Is it possible that the intense gravity of a black hole converts matter into antimatter? Does this mean that matter or energy that goes inside the black hole is converted to antimatter?
1
vote
1answer
54 views

Does 2 merging black holes necessarily make a quasar?

2 black holes are about to merge to become a larger black hole. Does this mean it'll become a quasar? From what I know, quasars are supermassive black holes or a collective amount of them. So, if it ...
2
votes
2answers
144 views

If quasars are powered by black holes, why are they so bright?

If a black hole can swallow everything, even light, then how can a black hole power anything, particularly something as bright as a quasar. Why doesn't the black hole swallow the light of the quasar? ...
3
votes
1answer
103 views

Can we see the past image of Earth because of curving light by massive objects?

I know massive objects can curve light, can we capture the image of past Earth by lights from Earth that curved by massive objects?
3
votes
2answers
121 views

What happens when two black holes collide? [duplicate]

There are many hypothesis saying that there will a collision between the milky way and Andromeda galaxy...so what happens when two black holes will collide?? And how will it effect the other objects ...
4
votes
1answer
135 views

Why is metallicity important in the death of stars?

I always thought that mass was the sole determinant of a star's fate. Then I saw the table here. So why does metallicity influence a star's ability to become a black hole or neutron star? Does it have ...
6
votes
3answers
337 views

Could there be dark matter black holes?

Could dark matter compress and form black holes? Since dark matter is even more abundant than normal matter, a dark matter black hole should not be rare...right?
2
votes
1answer
134 views

Can we draw a min(distance) and max(mass) relation based on current observation data of nearby astronomical objects within several parcsecs?

The data precision now can exclude a >>$1M_{\odot}$ black hole, which has a , say 10000 year orbital period with our sun? We can draw a two dimensional diagram(Mass VS. distance) to show the region ...
3
votes
0answers
78 views

How does light so travel so fast?. [duplicate]

I've read that photon's have zero mass, hence no force is needed to accelerate them. But then the second question. How can gravity affect something which has 0 mass?. Yes, gravity(black hole) can bend ...
8
votes
4answers
797 views

two black holes orbiting each other within their event horizon

Is there any argument against this situation: two black holes, one within the event horizon of the other, and the system is stable. It is interesting to me because that if this works, we could have ...
3
votes
2answers
410 views

Can things move faster than light inside the event horizon of a black hole?

Black Holes are regions of space where things get weird [Citation Needed]. Past the event horizon of a black hole, any moving particle instantaneously experiences a gravitational acceleration towards ...
7
votes
2answers
840 views

How is a non-rotating black hole created

How are non-rotating black holes formed? I guess that non-rotating black holes are formed from non-rotating stars but I couldn't find any proof that such a star exists on the internet. If this is ...
2
votes
1answer
108 views

Is it possible to have a part of space devoid of matter?

I have recently read this article and I am finding it a little hard to believe that there would be a place that is without matter. So, if there is a galaxy at the other side of the void, we would be ...
2
votes
1answer
130 views

What particles does a black hole emit when it evaporates itself?

Due to Hawking Radiation, after a very long time, a black hole will eventually disappear. But where does this "evaporation" go? What is this made of?
3
votes
2answers
233 views

Can stellar black holes cancel each other?

Hypothetical question: when a pair of identical stellar black holes are very close to one another wouldn't the side facing each other experience lower gravitational force? How is this logic un/sound?
2
votes
3answers
353 views

How small would you have to crush an object for it to become a black hole?

I was wondering how much you had to crush an object for it to become a black hole. Recently I learned that anything could become a black hole (even you) if it were crushed down small enough, for ...
3
votes
0answers
50 views

If nothing can pass the schwarzschild radius, how can black holes even start? [duplicate]

From our point of view, no object can fall into a black hole in finite time. The object will seem to be more and more red-shifted to us, but it will never quite pass the schwarzschild-radius / event ...
3
votes
2answers
253 views

Is our universe included inside a black hole?

This question repetitively comes to my mind but I've never found any good scientist article to argue about it, only esoteric or speculative web articles without much valuable background. So let's ...
3
votes
2answers
306 views

Interstellar movie: What is the “portal” to the other galaxy?

I recently watched Interstellar with some friends and we didn't come to the same conclusion. In my opinion, the portal they use to go to the other galaxy (to visit the three planets) is not a black ...
3
votes
1answer
253 views

Eternally collapsing objects?

As has been pointed out by some scientists, that black holes aren't stable bodies but are eternally collapsing objects. How does one come to such a conclusion? Is hawking radiation related to this in ...
2
votes
2answers
84 views

Is mass+energy conserved when a new universe forms inside a black hole?

My understanding is that there are credible theories out there in which the formation of a singularity in a black hole also represents the beginning of a new universe via a big bang. We can't see the ...
1
vote
1answer
77 views

Collapse of a star below the mass of Chandrashekhar Limit

How is Chandrashekhar Limit calculated? What happens to stars below the mass of the Chandrashekhar limit after they collapse?
4
votes
1answer
137 views

Is radiation from neutron stars delayed by time dilation?

I understand a neutron star to be the densest stuff that can exist without becoming a black hole, the densest thing which directly gives off radiation we can detect. At the event horizon of a black ...
3
votes
4answers
435 views

Mini black holes, a possible result of the LHC experiment at CERN

A scientist at CERN LHC (Large Hadron Collider) was asked during an interview about the possible results and consequences of operating the LHC at full power of collision in the near future, one of the ...
2
votes
1answer
117 views

Star versus Black Hole

I'm making a simplified animation for college project on how a star reacts with a black hole. I had known that a black hole sucks in everything and thus should be doing the same for stars. But upon my ...
2
votes
1answer
104 views

How can a supernova affect black hole in a binary system?

Suppose in a binary stars system there is a dying star and a companion black hole as they orbit around each other. My question is what will possibly happen to the black hole if the partner goes ...
4
votes
1answer
129 views

How Does Black Hole Evaporation Look From the Inside?

Imagine you're inside a black hole event horizon. The curvature of spacetime is such that the direction towards the singularity becomes timelike, as reverse movement becomes literally impossible. How ...